Hmm, I see you disagree with the authors of one of the sites you posted earlier:

I do disagree with the idea that sans serif fonts are easier to read on screen, particularly if your reading text. They're great for headlines and work well on billboards. But serif fonts have more uniqueness--letter for letter--than sans serif fonts, making them easier to read. Take a look at S and 5, B and 8, g and q, l and I in serif and sans serif, for example.

this is over a year later from an ipad. For whateve it's worth, on iphones and ipads one double spaces at the end of a sentence, and it automatically adds the period. I just added a space aft the period, which could make some of you happier. On the other hand, the touch screen has a tendency to add or drop letters as a result of either not hitting the key hard enough or accidentally brushing another key.

I have an iPhone and know what you're talking about. However, when you double space to add a period automatically, you end up with the period and ONE space before the subsequent word. Try deleting and counting the deleted spaces and I think you'll find that the iPad is the same.

And, at least on this site, it doesn't matter how many spaces you put in after the period. It's always chopped down to one. As in this message. I put 5 spaces after each period. At least on screen I did. They're all gone.

Life is like playing chess with chessmen who each have thoughts and feelings and motives of their own.

Ask yourself the question, "Do I want my text to be pretty, or do I want it to have maximum legibility?" I opt for maximum legibility. When I was a printer I read a stylebook that contained a legibility study. I did not make the tests myself. The stylebook said that simple Roman fonts, such as "Times New Roman" were the best for legibility and for saving space. It also said that the habit of "justified text", having each line the same length no matter how many letters were in the line, was pretty but not nearly as legible as "ragged right", the way it appears when using typewriter. The guide also said that double spaces at the end of a sentence enhance readability. Blank lines between pargraphs were recommended but indents were said to be acceptable. Effects such as "hanging indents" were frowned upon.

I wish I had the guide to quote, but my copy is long gone. It was written sometime the 1960s but I don't know on whose authority. What you are reading now is called a Gothic font. It is more aesthetically pleasing but is much harder to read than a Roman font. For legibility, italics are definitely out. Bold type is good for emphasis. With my old eyes, I type everything in large bold type. I typed this offering in a large bold Times Roman font on Microsoft Word and then copied it into this space.

For a forum, I am willing to go along with whatever the forum uses. If I can't read it, I just copy it into Microsoft Word and change type style and point size.

White paper or background and black letters enhance legibility. Script fonts are definitely less legible and should be used only if a classy look is wanted. All upper case or all lower case letters are less legible than upper and lower case letters combined according to capitalization rules.

You mentioned colors. I'm about to gripe to news stations about writing white on yellow, which is indecipherable on my 48in screen. I also find myself frequently hittlng alt-a to select all and make white letters when the type is black or blue on blue or black background. I have no trouble reading stuff on this site. No one taught me to type, so I always just skijpped one space. I was 40 before I learned the two space concept.